ceph [ -m monaddr ] [ -w | command ... ]


ceph is a control utility for communicating with the monitor cluster of a running Ceph distributed storage system.

There are three basic modes of operation.

Interactive mode

To start in interactive mode, no arguments are necessary. Control-d or 'quit' will exit.

Watch mode

Watch mode shows cluster state changes as they occur. For example:

ceph -w

Command line mode

Finally, to send a single instruction to the monitor cluster (and wait for a response), the command can be specified on the command line.


-i infile

will specify an input file to be passed along as a payload with the command to the monitor cluster. This is only used for specific monitor commands.

-o outfile

will write any payload returned by the monitor cluster with its reply to outfile. Only specific monitor commands (e.g. osd getmap) return a payload.

-c ceph.conf, --conf=ceph.conf

Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf to determine monitor addresses during startup.

-m monaddress[:port]

Connect to specified monitor (instead of looking through ceph.conf).


To grab a copy of the current OSD map:

ceph -m osd getmap -o osdmap

To get a dump of placement group (PG) state:

ceph pg dump -o pg.txt


A more complete summary of commands understood by the monitor cluster can be found in the online documentation, at


ceph is part of the Ceph distributed storage system. Please refer to the Ceph documentation at for more information.



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